Wang Kai, Shao Changlei, Jiao Xiangdong, Zhu Jialei, Cai Zhihai, Li Congwei
School of Mechanical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
Shanghai Nuclear Engineering Research & Design Institute, Shanghai 200233, China.
Materials (Basel). 2021 Aug 24;14(17):4774. doi: 10.3390/ma14174774.
Taking S32101 duplex stainless steel as the research object, underwater laser wire filling welding technology was used for U-groove filling welding. The influence of different shielding gas compositions on the ferrite content, microstructure, mechanical properties and pitting corrosion resistance was studied by simulating a water depth of 15 m in the hyperbaric chamber. The results show that, under the same process parameters, the size and proportion of austenite in the weld when using pure nitrogen as the shielding gas are larger than those protected by other shielding gases. In a mixed shielding gas, the increase in nitrogen content has little effect on the strength and toughness of the weld. Regardless of the shielding gas used, the base metal was the weakest part of the weld. At the same time, intermetallic inclusions have an adverse effect on the impact toughness of the weld. The pitting corrosion resistance of the welds depends on the CrN content in the heat-affected zone. The precipitation and enrichment of CrN causes local chromium deficiency, which is the main factor for the weak pitting corrosion ability of the heat-affected zone. Pure nitrogen protection has a better corrosion resistance than other gas protection.
以S32101双相不锈钢为研究对象，采用水下激光填丝焊接技术对U形坡口进行填充焊接。通过在高压舱内模拟15 m水深，研究了不同保护气体成分对铁素体含量、微观组织、力学性能和点蚀抗性的影响。结果表明，在相同工艺参数下，以纯氮气作为保护气体时焊缝中奥氏体的尺寸和比例大于其他保护气体保护时的。在混合保护气体中，氮气含量的增加对焊缝强度和韧性影响不大。无论使用何种保护气体，母材都是焊缝中最薄弱的部分。同时，金属间化合物夹杂物对焊缝冲击韧性有不利影响。焊缝的点蚀抗性取决于热影响区的CrN含量。CrN的析出和富集导致局部铬缺乏，这是热影响区点蚀能力较弱的主要因素。纯氮气保护比其他气体保护具有更好的耐蚀性。
